对牛弹琴 = to play the lute to a cow (idiom); fig. offering a treat to a unappreciative audience / to cast pearls before swine / caviar to the general / to preach to deaf ears / to talk over sb's head http://www.mdbg.net/chindict/chindict.php?page=worddict&wdrst=0&wdqtm=1&wdqcham=1&wdqt=%E5%AF%B9%E7%89%9B%E5%BC%B9%E7%90%B4http://www.mdbg.net/chindict/chindict.php?page=worddict&wdrst=0&wdqtm=1&wdqcham=1&wdqt=%E5%AF%B9%E7%89%9B%E5%BC%B9%E7%90%B4

对牛弹琴 1) to talk about something to someone that is beyond their level of understanding. In English, we use the phrase: "to talk over somebody's head", "to talk over their heads" 2) 英文成语：“cast pearls before swine”：to share something of value with those who will not appreciate it.

有道查来的 play the lute to a cow to have [choose] the wrong audience; cast [throw] pearls before swine; play one's guitar to an ox; preach to deaf ears; talk of ice to a butterfly; talk over people's heads; thrum the lute before a buffalo; waste good acts on sb. who won't understand; waste one's effort; whistle jigs to a milestone